Trac #34157: Meta ticket: fix docstring markups

Originated from #30448.

We fix

​https://github.com/sagemath/sagetrac-
mirror/runs/7294638131?check_suite_focus=true

by chunks through

- #34156: sage/game_theory
- #34158: sage/manifolds
- #34159: sage/modular
- #34160: sage/schemes
- #34161: sage/databases
- #34162: sage/doctest
- #34163: sage/interfaces
- #34164: sage/plot, sage/graphs
- #34165: sage/tests/book_stein_modform.py
- #34166: sage/tests except sage/tests/book_stein_modform.py
- #34167: sage/matroids, sage/geometry, sage/modules
- #34168: sage/categories
- #34169: sage/interacts and sage/rings
- #34170: sage/coding
- #34171: sage/combinat
- #34172: sage/groups, sage/misc

and a few commits that finish the job here on the ticket.

URL: https://trac.sagemath.org/34157
Reported by: klee
Ticket author(s): Matthias Koeppe
Reviewer(s): Kwankyu Lee

.github/workflows/lint.yml

@@ -50,5 +50,3 @@ jobs:
       run: pip install tox
     - name: Lint using tox -e rst
       run: tox -e rst
-      # Until all errors are fixed:
-      continue-on-error: true

src/sage/doctest/sources.py

@@ -764,8 +764,8 @@ def _test_enough_doctests(self, check_extras=True, verbose=True):
         INPUT:
 
         - ``check_extras`` -- bool (default ``True``), whether to check if
-          doctests are created that do not correspond to either a ``sage: ``
-          or a ``>>> `` prompt
+          doctests are created that do not correspond to either a ``sage:``
+          or a ``>>>`` prompt
 
         - ``verbose`` -- bool (default ``True``), whether to print
           offending line numbers when there are missing or extra tests

src/tox.ini

@@ -207,6 +207,7 @@ rst-roles =
     trac,
     wikipedia
 rst-directives =
+    attribute,
     automethod,
     autofunction,
     toctree,
@@ -219,7 +220,9 @@ extend-ignore =
     # Ignore RST306 Unknown target name -- because of references to the global bibliography
     RST306
 exclude =
+    # Avoid errors by exclude files with generated docstring portions such as {PLOT_OPTIONS_TABLE}
     sage/combinat/designs/database.py
+    sage/graphs/graph_plot.py
     sage/misc/sagedoc.py
 
 [pytest]